The invention relates generally to structures and materials having improved tolerance to impact damage and more specifically concerns reducing the damage done to materials by the shock waves produced by impacting projectiles.
Most attempts to improve the impact damage tolerance of graphite fiber reinforced epoxy matrix composites have worked with new resins, new curing techniques, or new fiber types and orientations. In addition, novel structural geometries have been introduced which are themselves damage tolerant in that material damage/failure at a point of impact is not catastropic to the entire structure.
While these attempts to improve material properties and structural insensitivity have been quite successful, they have not included a major factor in high velocity damage--the damage done by the acoustic shock wave generated by the impacting projectile. By not including the correct physical acoustic model, optimum use of given materials and structural designs have been wanting.
It is therefore the primary object of this invention to reduce the damage done to materials and structural designs by acoustic shock waves generated by impacting projectiles.
Another object of this invention is to utilize the correct physical acoustic model to obtain optimum use of materials and structural designs in impacting projectile environments.
A further object of this invention is to provide a backing for materials and structural design that has an acoustic impedance which couple acoustic shock waves out of the materials or structural design and thereby reduce the damage done by shock waves generated by impacting
Still another object of the invention is to improve the impact tolerance of multiple lamina materials with acoustic impedance variations through the lamina thicknesses.
Other objects and advantages of this invention will become apparent hereinafter in the specification and drawings.